Australia is pretty dry at the moment. In fact we've had a drought in recent years. The dam in my city are only 30% capacity.No, the reason road bikes are poor choices for commuting are:
1) They aren't very resilient, and need a lot of attention with regards to tire inflation.
2) Most people use them with clipless pedals, which means you have to wear special shoes to ride them.
3) They're comparatively dangerous in wet weather.
4) You can't put a rack on them, so they're not very good at carrying stuff.
5) They're the most expensive bikes around, so you have to worry about theft a lot more.
If you intend to put fenders and larger tires and lights and a rack on your road bike, what you've essentially done is make your own touring bike. Nothing wrong with that, but you might end up spending more money than you needed to spend.
Two academics I've seen ride road bikes with racks. Although they have old road bikes. The ones where the gears are not changed at the handle bars.